Method and apparatus for treating sheets



March 20, 1934. I N, B. oRNlTz 1,951,756

METHOD AND APPARATUSQFQR TREATING SHEETS Filed May 19, 1950 INVENTOR4Piitented Mar. 2o, 1934 l 1.951.766 i METHOD AND Arranilig'rns ro TammoSHE Nathaniel B. omitz,

Pittsburgh, ra., assit-nor tu National Alloy Steel Company, Blawnox,Pa., a

corporation of Pennsyl Vania Application May 19, 1930, sei-iai No.53,482 1 c. (ci. 2st-c) My inventionr relates to theheat-treating orannealing of sheetsand, in particular, .contemplates a novel method andapparatus for convey- .ing the sheets through an annealing furnace.

It has been -found that the steel rolls forming the conveyors now usedfor passing sheets through an annealing furnace tend to collect coats ofoxide which are rough and pointed so that sheets passing thereoverbecome scratched and dented. Such sheets, of course, are not perfect andmust be 'scrapped or given an inferior grade by the inspector. In someinstances, it has been the practice to place a perfect sheet on top ofan imperfect sheet. lresting on the conveyor rolls. 'I'he top sheet'isthus protected to some extent from abrasion by the rolls,` although, inmany instances, the upper sheet is dented through the lower one by theprojections from the conveyor rolls. l

When the rolls reach this stage of oxide coating, it is necessary toshut down the furnace until the rolls can be polished by grinders. Thisshutting-down is along process and is a serious curtailment to theproduction of the furnace. A period of several days is necessary forcooling the furnace and further time is required forthe actual polishingof the rolls before the furnace can again be placed in service. i l

I have invented a method and means for passing sheets through anannealing furnace which avoids the objections above-mentioned. Accordingto the invention, I employ a conveyor having supportingelements formedof refractory or nonoxidizable material such as silicon carbide'. Suchsurfaces do not tend to form any oxide coat which would mar the iinishof the sheets passing through the furnace. In addition, the problem oflocalized chilling, which has been met with heretofore, is lsolved bythis construction.

For a complete understanding of the invention, reference is made to theaccompanying -drawing in which, v j y Figure 1 is a partialsideelevation of a conveyor constituting a present preferred embodiment ofthe invention;l f

Figure 2 is an end elevation;

Figure 3 is a top plan view of the portion of the apparatus shown inFigure 1; and

Figure 4 is a partial side elevation of a furnace havingy a modied formof conveyor therein.

' Referring in detail to the drawing, I provideA a conveyor composed ofa plurality of carriers such as that sho'w'n at 10. The carrier 10comprises a central vertical web portion 11, a bottom link portionlZ,and a top supporting portion 13. 12 of the carrier is connected, forinstance, by links 14.. and 15, tosimilar that shown at 10. A number ofVsuch 4carriers linked together form a coninuous conveyor passingthrough the annealing urnace, the oor of which is indicated schermatically at 16. The conveyor may be driven by any convenient source ofpower. The web portions 11 of the carriers 10 ride in a slot 17 in thedoor of the furnace and the links 14 and 15 and the bottom portions ofthe carriers pass through a channel 18 connecting with the slot.

The top portion of thecarrier is provided with fourprojecting arms 19,20, 21, and 22. At their outer ends, these arms support pads 23 "havingdovetailed slots 24 therein. .Refractory inserts 25, which may be ofvany suitable material such as silicon carbide, have dovetailedprojections 26 fitting into the slots 24. The inserts 25 afford a seriesof spaced'refractory supports for sheets being conveyed through thefurnace. Any suitable non-,oxidizing material may be used. for thesupporting inserts 25.

In operation, the conveyor is driven continuously and the vsheets areplaced individually on the carriers and so pass through the furnace. Nooxide coat forms on the refractory inserts 25 to scratch or dent thesurface of the sheets. Since there is no relative movement between thesupporting surfaceand the sheet in this type of conveyor, the latter iswithout a marl:` or blemish when taken from the delivery end of thefurnace. Because of the thermal qualities of the insert, no localizedchilling occurs and the nished sheet is uniformly treated throughout itsarea. Y

` A modified form of the invention is illustrated in Figure 4. Accordingto this modification, a roller conveyor is constituted by a plurality ofrolls 30.' The rolls 30 are provided with refracinserts 31 similar tothose shown at 25 in the first form of the invention. 'I'he inserts 31,of course, are curved tor conform to the surface of the roll 30 Theadvantages resulting from the preferred form of the invention are alsoinherent in the modiiied form shown in Figure 4.

Although I have illustrated and described but two embodiments of theinvention, the scope thereof is notllimted to the specific details ofthese modifications. Any changes may be made in the construction Withoutdeparting from the spirit of the invention as set forth in the aplsheets.

- NATHANIEL B. ORNITZ.

